The present invention relates to an information processing apparatus such as a personal computer, and more particularly, to a resume function for reproducing the work state that existed when a power source of the processing apparatus was turned off, upon turning on the power source again. The present invention also relates to a resume function in an information processing system which has a plurality of information processing apparatuses connected through a network.
Thanks to the advance of small device mounting techniques and development of power consumption reducing techniques in recent years, personal computers, work stations, word processors and so on (hereinafter they are called "information processing apparatuses") have become increasingly smaller in size, and even notepad-size products operable with a battery have recently been brought to the market. Such battery driven information processing apparatuses require a user to frequently shut off the power supply either manually or automatically in order to prevent the battery from being consumed in a short time. However, when the power source is to be turned off, the user is required to store user information, for example, a document under processing and so on, in a non-volatile storage unit, and moreover, when the power source is to be turned on again, the user must recall a program and the thus stored user information from the non-volatile storage unit. For this reason, such frequent turning-off of the power source causes a problem that efficient use of the apparatus is less likely for the user.
To attend to this problem, it is now common for a battery driven information processing apparatus be provided with a so-called resume function to store the contents of a display memory, I/O registers of input/output devices and so on in a main memory, and preserve the contents of the main memory by backing up the same with a battery before turning off the power source such that when the power source is again turned on, the contents of the display memory, the I/O registers of the input/output devices and so on preserved in the main memory are written back to the respective devices, and a state upon turning off the battery is reproduced as if the apparatus has been kept operating. Information processing apparatuses having such a resume function are disclosed, for example, in JP-A-57-17042 and JP-A-2-93814.
As described above, the resume function provides an excellent information processing apparatus which can reproduce a user's work state upon again turning on the power source and does not cause the degradation of the usability of the apparatus even if the power source is frequently turned off to reduce the consumption of the battery. However, the resume function hitherto provided in information processing apparatuses does not allow the user to perform another operation while preserving a work state. Also, when a plurality of users use a single information processing apparatus in which a user has preserved a work state using the resume function, another user, when turning on the information processing apparatus, will see the preserved work state of the previous user, thereby presenting unfavorable problems regarding security and utility.
Also, since the main memory is backed up by a battery to preserve a work state, the work state can be preserved only for a limited time period according to the capacity of the battery.
Further, the resume function hitherto provided in information processing apparatuses allows the user to reproduce a previous work state only on the same information processing apparatus in which the user interrupted work and preserved the corresponding work state, thereby preventing the user from operating the same work on different apparatus at various locations.
The conventional resume function provided in information processing apparatuses further implies a problem that a connection state to a network cannot be correctly reproduced.
The conventional resume function provided in information processing apparatus further presents a problem that a message such as an electronic mail transmitted through a network cannot be received during an automatic power-off state for reducing power consumption.